Domain Filtering¶

PyFIA provides flexible domain filtering to define your analysis population.

Land Type¶

The land_type parameter controls which land is included:

Value	Description	Filter Applied
`"forest"`	All forest land	`COND_STATUS_CD = 1`
`"timber"`	Timberland only	`COND_STATUS_CD = 1 AND SITECLCD IN (1,2,3,4,5,6)`
`"sampled"`	All sampled land	No filter

# Forest land only (default)
pyfia.volume(db, land_type="forest")

# Timberland (productive forest)
pyfia.volume(db, land_type="timber")

Tree Type¶

The tree_type parameter filters trees:

Value	Description	Filter Applied
`"gs"`	Growing stock	`TREECLCD = 2`
`"al"`	All live trees	`STATUSCD = 1`
`"sl"`	Sawtimber	`DIA >= sawlog minimum`

# Growing stock volume
pyfia.volume(db, tree_type="gs")

# All live tree volume
pyfia.volume(db, tree_type="al")

Custom Domain Filters¶

For specialized analyses, use domain filters with SQL syntax:

Tree Domain¶

Filter trees by attributes:

# Large trees only
pyfia.volume(db, tree_domain="DIA >= 12.0")

# Specific species
pyfia.volume(db, tree_domain="SPCD IN (110, 111, 121)")

# Combined conditions
pyfia.volume(db, tree_domain="DIA >= 5.0 AND SPCD = 316")

Area Domain¶

Filter conditions/plots by attributes:

# Specific forest types
pyfia.area(db, area_domain="FORTYPCD = 201")

# Low slope areas
pyfia.volume(db, area_domain="SLOPE < 30")

# Specific ownership
pyfia.area(db, area_domain="OWNGRPCD = 40")  # Private land

Grouping Results¶

Use grp_by to stratify results:

# By single attribute
pyfia.volume(db, grp_by="SPCD")

# By multiple attributes
pyfia.volume(db, grp_by=["STATECD", "FORTYPGRPCD"])

Common Analysis Patterns¶

Species-Specific Volume¶

# Pine species volume on timberland
pine_volume = pyfia.volume(
    db,
    land_type="timber",
    tree_type="gs",
    tree_domain="SPGRPCD = 10"  # Softwood group
)

Sawtimber Analysis¶

# Sawtimber volume by species
sawtimber = pyfia.volume(
    db,
    vol_type="sawlog",
    land_type="timber",
    tree_type="sl",
    grp_by="SPCD"
)

Private Land Analysis¶

# Volume on private forest land
private_volume = pyfia.volume(
    db,
    land_type="forest",
    area_domain="OWNGRPCD = 40"
)